CVE-2019-5855 in Chrome
Summary
by MITRE
Integer overflow in PDFium in Google Chrome prior to 76.0.3809.87 allowed a remote attacker to potentially exploit heap corruption via a crafted PDF file.
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Analysis
by VulDB Data Team • 02/27/2024
The vulnerability identified as CVE-2019-5855 represents a critical integer overflow flaw within PDFium, the PDF rendering library that powers Google Chrome's document handling capabilities. This vulnerability exists in versions of Chrome prior to 76.0.3809.87 and enables remote attackers to potentially exploit heap corruption through the careful crafting of malicious PDF files. The flaw specifically resides in how PDFium processes certain numerical values during PDF parsing operations, creating conditions where integer arithmetic can exceed maximum representable values.
The technical nature of this vulnerability stems from improper bounds checking during integer operations within the PDF processing pipeline. When PDFium encounters specific malformed numerical fields in PDF documents, particularly those related to object sizes or array dimensions, the integer overflow can occur during calculations that determine memory allocation sizes. This overflow condition allows attackers to manipulate memory layout and potentially overwrite adjacent heap regions, leading to heap corruption that can be leveraged for arbitrary code execution. The vulnerability aligns with CWE-190, which specifically addresses integer overflow conditions that can result in memory corruption, and represents a classic example of how improper integer handling can create exploitable conditions in memory management operations.
The operational impact of CVE-2019-5855 extends beyond simple document rendering issues as it creates a remote code execution vector that can be exploited through web-based PDF viewing scenarios. Attackers can craft malicious PDF files that, when opened in vulnerable Chrome versions, trigger the integer overflow condition and subsequently lead to heap corruption. This exploitation pathway follows ATT&CK technique T1203, where adversaries leverage application vulnerabilities to execute arbitrary code, and T1059, which involves using command and scripting interpreters. The vulnerability affects not only end users but also enterprise environments where Chrome is the primary browser for document handling, making it particularly dangerous in corporate settings where PDF documents are frequently shared and opened.
Mitigation strategies for CVE-2019-5855 primarily focus on immediate version updates to Chrome 76.0.3809.87 or later, which contain the necessary patches to prevent the integer overflow condition. Organizations should implement comprehensive patch management procedures to ensure all Chrome installations are updated promptly. Additionally, network administrators can deploy web application firewalls or content filtering solutions to block suspicious PDF files, though this approach should complement rather than replace proper patching. Security teams should also monitor for exploitation attempts through network traffic analysis, looking for patterns consistent with PDF-based attacks. The vulnerability demonstrates the importance of maintaining up-to-date software libraries and the critical nature of memory safety in browser components, as PDFium's heap management directly impacts overall browser security posture. Organizations should also consider implementing sandboxing mechanisms and privilege separation to limit the potential impact of successful exploitation attempts.